How to extract data out of a specific PHP array - php

Question

I have a multi-dimensional array that looks like this:
The base array is indexed based on category ids from my catalog.
$cat[category_id]
Each base array has three underlying elements:
['parent_id']
['sort_order']
['name']
I want to create a function that allows us to create a list of category_id's and names for a given parent_category_id in the correct sort order. Is this possible? Technically it is the same information, but the array is constructed in a weird way to extract that information.
Here is an example definition for the array:
$cat = array();
$cat[32]['parent_id']= 0;
$cat[32]['sort_order']= 1;
$cat[32]['name']= 'my-category-name1';
$cat[45]['parent_id']= 0;
$cat[45]['sort_order']= 0;
$cat[45]['name']= 'my-category-name2';
$cat[2]['parent_id']= 0;
$cat[2]['sort_order']= 2;
$cat[2]['name'] = "my-category-name3";
$cat[3]['parent_id']= 2;
$cat[3]['sort_order']= 1;
$cat[3]['name'] = "my-category-name4";
$cat[6]['parent_id']= 2;
$cat[6]['sort_order']= 0;
$cat[6]['name'] = "my-category-name5";

Answer 1

Assuming it's something of this sort:
$ary = Array(
0 => Array(
'parent_category_id' => null,
'sort_order' => 0,
'name' => 'my-category-name0'
),
1 => Array(
'parent_category_id' => 0,
'sort_order' => 1,
'name' => 'my-category-name1'
),
2 => Array(
'parent_category_id' => 0,
'sort_order' => 2,
'name' => 'my-category-name2'
),
3 => Array(
'parent_category_id' => null,
'sort_order' => 0,
'name' => 'my-category-name3'
),
4 => Array(
'parent_category_id' => 3,
'sort_order' => 0,
'name' => 'my-category-name4'
)
);
You can use a combination of a foreach and usort to achieve what you're going for.
// #array: the array you're searchign through
// #parent_id: the parent id you're filtering by
function getFromParent($array, $parent_id){
$result = Array();
foreach ($array as $category_id => $entry){
if ($entry['parent_category_id']===$parent_id)
$result[$category_id] = $entry;
}
usort($result,create_function('$a,$b','return ($a["sort_order"]>$b["sort_order"]?1:($b["sort_order"]<$a["sort_order"]?-1:0));'));
return $result;
}
var_export(getFromParent($ary,0));
EDIT Sorry, fixed some syntax errors. Tested, and works (at least to result in what I was intending)
EDITv2 Here's the raw output from the above:
array (
0 =>
array (
'parent_category_id' => 0,
'sort_order' => 1,
'name' => 'my-category-name1',
),
1 =>
array (
'parent_category_id' => 0,
'sort_order' => 2,
'name' => 'my-category-name2',
),
)
(Used var_export just for you #FelixKling)
EDITv3 I've updated my answer to go along with the OP's update. I also now make it retain the original "category_id" values in the result array.

Answer 2

First you create an empty array, it will be used to store your result.
$result = array();
You need to iterate through your initial array, you can use foreach().
Then, given your parent_category_id simply use an if statement to check whether it's the given id or not.
If it is, just construct and push your result to your $result array.
Use any of the sort functions you like
Use the magic return $result;
You're done.

Answer 3

function returnSortedParents($categories, $target_parent){
$new_list = array();
foreach($categories as $index => $array){
//FIND ONLY THE ELEMENTS MATCHING THE TARGET PARENT ID
if($array['parent_category_id']==$target_parent){
$new_list[$index = $array['sort_order'];
}
return asort($new_list); //SORT BASED ON THE VALUES, WHICH IS THE SORTING ORDER
}